When multiple decks are in play in Blackjack, the basic strategy remains the same, but adjustments are needed, particularly in terms of betting and risk management. With more decks, the odds shift slightly, so if you're using card counting, you'll need to adjust your bets based on the true count, which accounts for the number of decks remaining. This becomes especially important because the variance increases in multi-deck games. In terms of gameplay, while your decisions for doubling down or splitting may not drastically change, the increased number of cards in play slightly alters the likelihood of drawing high cards, which can impact your strategy. Additionally, the dealer’s probability of busting changes with more decks, so you should keep that in mind when deciding to hit or stand. Overall, while the core Blackjack strategy doesn't change, understanding the dynamics of multiple decks can help fine-tune your decisions, particularly if you're counting cards or managing your bankroll effectively.